Tapping head for threading machines



Ai 8 119390 F. J. sHRuM 1,772,018

TAPPING HEAD FOR THREADING MACHINES Fil ed April 14, 1926 s Sheets-Sheet 1 A g- 5 1930 P. J, SHRUM 1 712,018

TAPPING HEAD FOR THREADING MACHINES Filed April 14 1926 3 Sheets-Sheet 2 tapping head from the machine is facilitated. Inasmuch as threading machines of the Patented Aug. 1930 S T i PETER J;sHRUM, or ivro moa'nn enrs; rENivsYLvAnrA, assieivoitroirrrrsnonon 'SCREW AND BOLT COBPQRATIQN, orrrr'rsiauaen, EPENNSYLVANIAQA"CORPORATION OF PENNSYLVANIA 7 Application filed April 14,

This invention is for animprovement in threading machines, and relates more particularly to an improvement in a -tapping head for threading machines for forming an interior thread on pipes, pipe couplers, thread protectors and the like.-

Tapping heads for threading machines are in use at the present time wherein there are,

from the head without'the removal of the plate which retained all of the chasers in.

place. Diiiiculty has also been encountered in obtaining the desired range of adjustment for the. expanding movement of the cuttersriccording to the present invention, it is proposed to provide a tapping head wherein anyoneof the several chaser-s may be removed Without disturbing the other chasers or the retaining plate common to all of the chasers.

It is also proposed to provide means by whicln avwide range of adjustments for the cutters may be procured.

A further ob ect of the present invention is to provide in a machine of this kind a structure by means of which the removal of the tyje to which the present invention relates are well known in the art, I have illustrated, in the'accompanying drawings, only so much of the machine as is necessary for the understanding of my invention. In the drawings:

Figure 1 represents a side elevation of a tappfng headin position in a tapping machine, part of the headbeing shown in sec tion' 2 is a fragmentary section on line IIII of Fig. 1, the section being at right angles to that shown in Fig. 1; I

Fig. 3 is a horizontal section on lineIII- IIIoiiFig.1;."

Fig. 4 is a horizontal section through the on their outer ends.

TAPPING HEAD FOR THREADING MACHINES 1926. Serial no. 10i,'951.

lower of the tapping head, uise'cnbn bemg ,in the plane of line IVIV of Fig. '1; Fig. 5 is a vertical section throughthe low- .er part of the tapping headin substantially the planeof line VV of F ig; 4 o F ig. 6 a view similar tolfig. 4 onlyi'a fragment of the headwith aslightIYmQdified form of'chaser or cutter being shown; Figs. 7 to 10 inclusive, are sidejelevati'ons showing four'successive positions of the head in the threading operation.

:In the'drawings, 2 deslgnatesa rotaryand vertically reciprocable portion of a standard threading machine, and 3 designates the usual control rods at the sides of the machine,

I .Received within the end of the part 2 is the reduced shank porti0n4o'f the tapping head which has a stem portion 5 and a head portion 6. The reduced portion 4: may be atpiachezd to the part 2 by meansof a transverse 8y 1 v.

Passing through the stem portion 5 of'th'e cutter head is a transverse opening .8. Com municating with the opening Sisan axially extending bore9 which passes from the lower end of the head up through the stem, termiQ nating at the cross passage 8. 3

In the head porti'n 6 are radially arranged slots 10 which extendfrom the inner bore 9 out to the periphery ofthe head. The periphery of the head is of the a plurality of usualshapephaving the clearance grooves therein as ordinarily prov ded- 'Recelved in" each one of the radial "slots is a cutterorf chaser 11 having thread cutting portions 12' ,The innerends of the chasers terminat'e'ini the central bore and each cutter is provided. on its inner end with an incl ned or tapered heel portion 13. Several cutters llare re tained in the slots by, means of a plate 14secured'to the lower end face of the'head. In

eachof the Chasers on the edge thereof adj acent the plate '14 is a short slot'15. A spring projected pin'16 carriedby the plate 14 engages in the slot 15 for preventing the radial removal ofthe chasers, while permitting a limited radialvmovem'ent thereof. A

'inl6is rovided for each one of the several p. p. p nchasers.

WVith this arrangement, it is possible to secure the desired radial movement for the cutters and yet confine the cutters against movement beyond a desired range. The arrangement also permits of the removal of any single cutter or chaser without disturbing the remaining chasers. To remove any cutter or chaser, its pin 16 is pulled down'until the inner terminal of the pin is entirely withdrawn from the slot 15. When'the pin has been so withdrawn, the chaser may be removed radially from the head.

Operable in the central vertical bore 90f. the head is a rod 17 having an expander or mandrel 18 at its lower end. The upper endof the mandrel is screwed into a cross bar 19 in the'transverse slot 8 in the stem of thehead. The cross bar 19 has reduced'terminal portions 20 which are received in an annular groove 21 on the interior of a threaded nut The nut 22"-is screwed onto a threaded sleeve 23 sli'dable on the stem por'tion'5 of the head. The sleeve 23 has an annularly grooved flange 24 at its upper end.

In the cross bar 19 is a set screw 25 for adjusta'bly holdingthe mandrel 17' against turning with respect tothe crossbar 19. Upon releasing the set screw 25, the mandrel 17 may be turned toraise or lower it with respect to the cross bar by means of its threaded connectionwitht'he cross bar, and thereby vary the effective operating position ofthe mandrel.

The nut 22 is provided with spaced-apart holes 22 at different points thereahout, by

" means of which access may be had to theset screw 25. By turning the nut 22 on the sleeve 23, the nut 22 may be raised or lowered on the sleeve and thereby raise or lower the cross bar 19, and in this manner, the effective operating position of the mandrel with respect to the tapping head andrthe sleeve 23 may be adjusted.

Engaged in the annular groove 24*, .ofthe flange 24, are opposed yoke members 26 which are preferably less than acomplete semi-circle, so that the terminals of the yolres are spaced apart as best shown in Fig. 3. The yoke members 26 have supportinglugs 27 thereon, which are bolted at 28 to sleeve members 29 slidable on the side rods 3. With the arrangement as herein provided, the yokes 26 may move up and down with the up-and-down movement of the entire tapping head, thereby sli-dingthe-sleeve members 29 on the rods 3. At the same time, the yokes can be removed by merely uncoupling the bolts 28 when it is desired to remove the tapping head, so that it becomes unnecessary to remove the sleeves 29 entirely from the rods 3 as has heretofore been the-practice in machines of this type. "Carried in the flange 24 are a plurality of spring actuated detent members 30, having terminal portions 31, which are yieldably urged into sockets 32 in hardened steel plates 33 in the upper part of the stem 5. The purpose of these detents will be hereinafter more fully explained.

Arranged on the rods 3 in the usual manner, are lower limit nuts 34 and upper limit nuts 35. These nuts define the limit of travel of the sleeves 29. Since the sleeves 29'are rigidly connected with the yokes 26, which are engaged into grooves 24 in the sleeve 24, the

nuts 34 and- 35 limit the up and-down moveahle mandrel '18 is in its elowermost'position,

and in this position its tapered 'face bears against the tapered heels 13 of the chasers 11. This is clearly shown in Fig. 5. tapered head 18 otthe mandrel in this position prevents the chaser-s from being pushed radially inward. As the tapping head moves down in the usual operation of the machine, the mandrel 18 stays inthis position until the blank A has'been threaded to the desired depth.

Upon reaching the termination of the threading movement, the sleeves 29 engage the-lower limit nuts 34. The parts are then in the position shown in Fig. 8. The chuck 2 with thetapping head continues to move down a slight distance, while the yokes 26 prevent the sleeve'23 from going down with the head. Therefore, as the head continues to move down, the mandrel 17 with itsexpander 18 remains stationary. The head will continue'to move down'until the expander 18 is entirely above the heels '13, whereupon the cutters may'contract out of thread cutting position. As the tapping head moves down after the sleeve 23 has been stopped from downward movement, the spring projected detents 30 will function to force the terminals 31 into the sockets or [recesses 32. This operation otthe, detents will occur-just when'the tapping head has reached itslowermost position.

At this time, the part 2 will start to lift, raising the entire tapping head assembly. The detents :30 will function during. this upward movement. of the head to prevent the sleeve 23 from dropping by its own weight into a position where the expander 18 would again force the cutters out. As the part2 continues to lift, the sleeves 29 will be brought into engagement with the upper limit nuts 35. This will prevent the further upward movement of the sleeve 23,.but thetapping head will continue to move upwardly a slight distance, thereby forcing the yieldable .de-

The

tents out of holding position; At the same time, the relative upward movement of the stem 5 with respect to the' sleeve 23 willjj'eaus'e a corresponding relative. movement between the then stationary expander ld and the upwardly :moving cutters. This relative movement will continue until the expander 18 has again forced the chasersoutand isiin the position shown in'F ig.:5.' This is also the position of the parts in'FigQZ'. 1 j

When' 'the chasers have :been' forced outagain and the mandrel is setto hold them from retracting; the movement ;of"the part .2. will be reversed and the next threadingoperation canbe proceeded'withi Y a.

-By reason of the arrangement herein-provided, a very r delicate adjustment of the mandrel with respect to the cutters can be readily'eliected. One adjustment is obtain able by releasing the set' screw 25 and screwing the threaded upper-.end of the mandrel Tupi or down inthe cross bar 19.- A second adjustment can be obtained screwing the nut 22 up or down on the threaded sleeve 23. By thecombination of thesetwo adjustments, quite a wide variationis obtainableand the adjustment can be very accurately made.

In the modification shownin Fi'g. 6, the chasers are so made as tdprovide for-still another adjustment. Inthis figure, 6 designates the head of the threader which has radial slots therein as hereinbefore described; The chasers are made of anouter part 11 and an inner part orfiller '11: v The two parts have interlocking end terminals as indicated at 119. This interlocking 'connection'betweenthe portions ll and 11 prevents any relative radial movement between the two parts. At, anytime that it is so desired, the part 11 can be removed by removing the entire chaser from its slot and-substituting a similar memberthereforywhich may be either longer or shorter a By inserting a longer- 'member 11 the diameter of the threader is increasedg while the substitution 0ft. shorter member 11 would permit the cutters to: retract to a greater extent. The parts 11 can be made up in sets which arevery closely graduated to obtain close adjustment of the several eutters. With this arrangement, it is also possible to substitute longer or shorter chaser members 11 while retaining the same fillers 11 It is also possible to replace a worn or broken section ll without necessitating the loss of the part 11*. It is proposed that these cutters will be retained in place by spring pins similar to the springpins 16 previously described. These pins are shown in Fig. 6 at 16.

The tapping head as herein disclosed has several advantages by reason of the fact that the chasers or cutters may be individually removed or replaced without disturbing the plate 14 which holds all of the chasers in the tapping head. Further advantages arise from the'two-part construction ofthe chasers asshown in Fig. 6. 4

Further important advantages secured by the present invention reside in the threaded connection between the cross bar 19 and the Still another important advantage of the present invention thearrangenient of -tl1e yoke'membersQG so that tney extend around the flan e 24: less than 180 and wherein these yokes are detachably connected with the sliders 29 so that the tapping'head'may be re 7 moved from the machine merely by removal of the nut 7, and disconnecting the bolts 28" without necessitating the removal of the slit ers 29' or the rods I claim: V

1. A tapping head for threading machines including a head memberhaving a shank portion,a plurality of chasers carried by the head 7 member, a mandrel for expanding thechasers,

a' sleeve slidable-on the shank,a cressmember passing through the shank, and a nut having an annular groove therein threaded on said sleeve, saidimandrel being threadedly con nected to the cross "member, said cross memher having reduced end portions adaptedto engage and cooperate with the annular groove in said nut. L 7

2. A tapping head for threading machines having ahead portion and a shank portion, a plurality of expansiblechas'ers in thehead member, a'vertically reciprocable element for expanding the chasers, a cross member-slidable in the shank with which the expanding means isconnected,'a sleeve reciprocable on the shank, and a nut threaded on the sleeve for vertical adjustmentysaid nut providing a connection 'between the cross member and the'sle'eveu 1 3. tapping head for threading machines including a head having expa'nsible: chasers therein,"mea1'1s for expanding the chasers in cludingamandrel and a reciprocabl'e sleeve with which themandrel is connected, said sleeve having a f flanged peripheral portion, and means for eiiecting'a relative movement betweeneth sleeve and the head, including a pairofside rods, a sleeve'oneachoir the side rods, limiting stops-on theside' rodsbetween which the sleeves are movable, and yokemein bers'detachably connected with each ofthe said sleeves which slide on theside rods, said yokes' each'fhaving a curvature of'less than a threading machine having a shank portion and a head member containing a plurality of radial slots therein, chasers having recesses therein adapted to be received in said'slots, a plate disposed on the end of the head portion having spring pressed pins therein engaging the recesses in said chasers limiting the radial movement thereof, and means forexpanding the chasers Within said limits including a vertically reciprocable mandrel, a cross member through which the mandrel is threaded permitting vertical adjustment of said mandrel, a sleeve reciprocably mounted around said shank portion having athreaded peripheral surface, an annular nut threaded on said sleeve and connected withsaid cross member for making a second verticaladjustment of said mandrel.

' 5. A tapping head for a threading machine having a shank portion and a head portion containing a plurality of radially adjustable chasers, a vertically reciprocable mandrel for expanding said chasers, a cross bar slidable in said shank and threadedly connected with said mandrel permitting. vertical adjustment of said mandrel, asleeve slidable on the said shank, an annularnut threaded on said sleeve and connected with said cross bar for vertically adjusting said bar and mandrel, and means for limiting the upward and downward movement of the sleeve and mandrel'to expand and contract the chasers during the operation of the machine.

6. A tapping head fora threading machine having a shank portion and a head portion containing a plurality of radially adjustable chasers, a mandrel and a cross bar threadedly connected therewith permitting vertical adjustment of said mandrel, a sleeve slidable onthe said shank, an annular nut'threaded on said sleeve and connected with said cross bar for vertically adjusting said bar and mandrel and means for limiting the upward and downward movement of thesleeve and mandrel to expand and contract the chasers during the operation of the machine,v said means comprising an extended flanged portion on said sleeve, a plurality ofarcuate yokes engaging said fiangedportion and supporting said sleeve, side rods having: sleeve engaging stops thereon limiting the movement of the sleeve for removably interengagin the mandrel and chasers.

A tapping head for a threading. machine comprising a head member having a shank portion, a plurality of radiallyadjustable chasers contained in said head member, means forradially expanding said chasers including a reciprocable sleeve on said shank portion connected therewith, means for limiting the movement of said sleeve in one ;direction relative to said shankportionduring operation of the machine for disengaging the expanding means a from :;the-;chasers,1 means for locking the; sleeveztoatheihead and means for limitingv the :movement of said sleeve in the opposite, directionrelative to said shank portion for releasing thesleeve from: the head to expand the chasers.

8. A tappinghead for a threading machine including aqhead member having a shank portion, a plurality :of chasers containedin said head-member,a mandrel 'ifor. radially expanding said chasers, means for making accurate adjustment in the expansion of said chasers so that the tooLmay be used'to thread blanks of. varyingv diameters, said means comprising, a cross bar slidablein said shank portion and through which the mandrel is threaded permitting vertical adjustment of the mandrel in-relation to said cross bar, a sleeve slidably mounted around said shank, an, annular nut ,threadedon said sleeve and connectedtosaid cross bar for r aising and lowering the cross bar making a, second adj ustment ofthe ,mandrel for controlling the expansion of the chasers and meansfor locking said. mandrel to the cross bar.

9. A tapping head for a threading ma chine comprising a head 1member having a shank portion, apluralityof adjustable chasers in said head member, .a'mandrel for expanding said chasers, a sleeve having extended flanged portions slidably mounted on said shank, means connecting saidmandrel with said sleeve, means for effecting relative movement between the sleeve and the; shank including a pairof side rods, a sleeve on each side rod, limiting,stops on eachside of said rodsbetween which-saidsleeves are slidable, a yoke connected :with each sleeve and engaging the flanged portion on said first mentioned sleeve, and means for locking said first sleeve to said shank when the said secand sleeves are engaging one set of stops and for unlocking said sleeveirom-saidshank when engaging the other of said stops.

In testimony (whereof I havehereuntonset my'hand,

PETER J. SERUM. 

